Hi
If it’s heating up I would try a and reseat all the connectors you disconnected and clean them with isopropyl alcohol while you are there
As for finding the fault so would get a microfibre cloth and dip it in isopropyl alcohol not so it’s dripping by enough
Then wipe the device and see where the alcohol evaporated first as that will point you to where it’s heating up and you can address it accordingly
Hopefully this helps
Thanks:-)